﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Security.Cryptography;

namespace SMALLERP.DataClass
{
    class ENCODE
    {
        private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };

        /// <summary> 

        /// DES加密字符串 

        /// </summary> 

        /// <param name="encryptString">待加密的字符串</param> 

        /// <param name="encryptKey">加密密钥,要求为8位</param> 

        /// <returns>加密成功返回加密后的字符串，失败返回源串</returns> 

        public static string EncryptDES(string encryptString, string encryptKey)
        {

            try
            {

                byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));

                byte[] rgbIV = Keys;

                byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);

                DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();

                MemoryStream mStream = new MemoryStream();

                CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);

                cStream.Write(inputByteArray, 0, inputByteArray.Length);

                cStream.FlushFinalBlock();

                return Convert.ToBase64String(mStream.ToArray());

            }

            catch
            {

                return encryptString;

            }

        }



        /// <summary> 

        /// DES解密字符串 

        /// </summary> 

        /// <param name="decryptString">待解密的字符串</param> 

        /// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param> 

        /// <returns>解密成功返回解密后的字符串，失败返源串</returns> 

        public static string DecryptDES(string decryptString, string decryptKey)
        {

            try
            {

                byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);

                byte[] rgbIV = Keys;

                byte[] inputByteArray = Convert.FromBase64String(decryptString);

                DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();

                MemoryStream mStream = new MemoryStream();

                CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);

                cStream.Write(inputByteArray, 0, inputByteArray.Length);

                cStream.FlushFinalBlock();

                return Encoding.UTF8.GetString(mStream.ToArray());

            }

            catch
            {

                return decryptString;

            }

        }
    }
}
